It was inevitable, and it's a good thing. Whoever gets the Democratic nomination must be able to handle attacks from multiple directions. Whatever the Dems can dish out, Rove and company will do worse.

So Dean is in the crosshairs.

Lieberman, desperate to get himself in the headlines, has been the most aggressive. Rather surprisingly, he was the only one to go after Dean hard in the last two candidate forums talking about such silliness as "Dean depressions" and insinuating that Dean would be worse than Bush on the economy.

As ridiculous as the charges might've been, it got Lieberman into the debate story ledes. If the latest poll results are any inidication, the attacks were a strategic error.

But now Gephardt has thrown the gauntlet, implying Dean and Gingrich are sort of ideological soulmates (while Kerry is still harping on the "Dean is too liberal" line).

Gephardt's motivation is clear.

1) The latest Zogby poll out of Iowa confirms that Gep is losing ground on that must-win state for him.

2) Gephardt is seeing the AFL-CIO endorsement slip away, and has nothing to lose by trying to pry the SEIU and AFSCME away from Dean.

Gephardt delivered his attack in the basement of the Teamsters hall on the outskirts of the state capital here, with union members sitting on metal folding chairs cheering him on. There was no mistaking how much importance the Gephardt campaign attached to in the speech, with the candidate dressed in a blue suit and white shirt and speaking from a teleprompter.

While my initial hopes were that the primary would remain clean, I've become convinced it's better this way. Let the candidates endure trial by fire, better to prepare them for the Mighty Wurlitzer and Rove machine. If Dean can't parry these assaults effectively, then he's not the best man for the nomination.

Of course, Dean would be in greater danger if his opponents could make up their minds over whether Dean was too liberal or a Gingrich Republican.